Nonrotating spool with optimum wire tension upon payout

ABSTRACT

An improvement to minimize payout tension of a wire on a nonrotating spool wherein the spool has a drum portion between inboard and outboard flanges, the improvement comprising the drum having outside diameters which progressively increase from the inboard end to the outboard end according to a desired maximum constant tension contour, and the wire being wound on the drum to form outside diameters which progressively increase from the inboard end to the outboard according to a desired minimum constant tension contour.

a i t Muted Mates Fatent [151 3,645,469 Fischer et a1. Feb. 29, W72

[54] NONRQTATHNG SPOOL WHH [56] References Cited ggggg WERE TENSEUN UPQN UNITED STATES PATENTS 2,980,362 4/1961 Goddard ..242/176 [72] Inventors: Edward G. Fischer, Verona; Albert ,1. 3,000,493 9/1961 Hirst ..242/128 X Molnar, Trati'ord, both of Pa. 3,021,092 2/1962 Whear1ey.. .242, 128

3,02,8 198 Lth ..21 [73] Assignee: The United States oi America as 4 5 9 9/ 6 a om 24 ll 7 X represented by the Secretary oi the Navy Primary Examiner Georg6 Mautz [22] Filed: 0% 24, 1969 Attorney-Justin P. Dunlavey and Ervin F. Johnston [21] App1.No.: 869,032 [57] ABSTRACT An improvement to minimize payout tension of a wire on a [52] 111.8. Cl ..242/118.4,242/l28,242/129, nonrotating spool wherein the spool has a drum portion 242/159, 242/176 between inboard and outboard flanges, the improvement com- [51] int. C1. ..B6511 75/ 114, B65h 49/02 prising the drum having outside diameters which progressively [58] Fieid oi Search ..242/I17, 128, 176, 118.4, 118.6, increase from the inboard end to the outboard end according 242/113 1 13 2 11 1131; 17 174 175 to a desired maximum constant tension contour, and the wire 159 129 being wound on the drum to form outside diameters which progressively increase from the inboard end to the outboard according to a desired minimum constant tension contour.

3 Claims, 4 Drawing Figures Patented Feb. 29, 1972 3,645,469

2 Sheats-$heet 1 OIRECTlON OF SPIN --OFF g :2 NON-ROTATING SPOOL |8 llluw" {K 22 I I I OUTLET I6 INBOARD I4 OUTBOARD FLANGE FLANGE FlG (PRIOR ART) 23 NON-ROTATING SPOOL DIRECHON OF SPIN-OFF V 28 ouraoano' FLANGE maoARo FLANGE 2 v INVENTORS. EDWARD G. FISCHER ALBERT J. MOLNAR BY ERVIN F. JOHNSTON ATTORNEY.

NGNIIRG'IIATING SWGI. WITH GPTIMIUM WIIRIE TIENSIGN UPON IPAYGIJT The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

In the wire guided torpedo concept a portion of a very fine filament guidance wire is coiled on a spool located on a mother vehicle and the other portion of the wire is coiled on a spool which is located in the afterportion of a torpedo. When the torpedo is launched the wire uncoils from both spools and lays substantially motionless in the water so that little strain is exerted thereon. Both spools are completely exposed to the water environment and each has a drum portion which is located between a pair of flanges. The wire, which is coiled on the drum, pays out from the outside periphery of the coil over one of the flanges, thence through a tube or opening which is aligned with the central axis of the spool.

A problem associated with present wire-guided torpedo spools is that the payout tension on the wire varies considerably as the wire uncoils between the spool flanges. For description purposes the flange over which the wire uncoils may be called the outboard flange and the other flange may be called the inboard flange. It can now be visualized that as the wire uncoils between the outboard and inboard flanges the payout tension progressively increases toward the inboard flange since the lengths of wire spinning in the water between the outboard flange and the turns of wire on the coil also increase. As this length of wire spins in the water during this uncoiling operation a considerable amount of hydraulic drag is applied to the wire and becomes a maximum for any layer of wire at the last turn adjacent the inboard flange of the spool.

We have found that this undesirable variation in payout tension in the wire can be minimized by providing the spool drum with a novel configuration and winding the wire on the spool so that it also assumes a novel configuration. By computer methods we have been able to plot constant payout tension contours for the wire on a graph illustrating spool radius versus spool length. As the spool length increases the payout tension on the wire increases because of the increasing length of wire spinning in the water off of the spool, however, this increasing tension can be balanced out by increasing the spool radius since an increasing radius decreases the payout tension on the wire. In the present invention the spool drum is configured with outside diameters which progressively increase from the outboard end to the inboard end according to a desired maximum constant tension contour, and the wire may be wound on the drum to form outside diameters which progressively increase from the outboard end to the inboard end according to a desired minimum constant tension contour.

An object of the present invention is to provide a nonrotating spool which is configured to minimize the variation in payout tension on a wire which is uncoiled from the outside along one end of the spool.

Another object is to provide a nonrotating spool with wire wherein both the spool and the wound wire are configured to minimize the variation in payout tension on the wire as it is payed out from outside the spool along one end thereof.

Other objects and many of the attendant advantages of this invention will be readily appreciated as it becomes better un derstood by reference to the description and accompanying drawings which follow.

FIG. 1 is a side view of a prior art wire guided torpedo spool with the wire coiled thereon;

FIG. 2 is a side view of the improved spool and wound wire.

FIG. 3 is a graph illustrating constant tension contours of a wire payed out from a nonrotating spool; and

FIG. d is an enlarged cross section through a top portion of the improved spool and wound wire illustrating the novel configurations to minimize variation of payout tension on the wire.

Referring now to the drawings there is shown in FIG. I a prior art nonrotating spool and wound wire. The spool 12 includes a cylindrical drum (not shown) which is located between outboard and inboard flanges l4! and Id. The wire In is wound in layers in a cylindrical fashion on the spool drum and is payed out over the outboard flange ll through a tube or opening 20 which is aligned with the central axis 22 of the spool. The opening 20 is normally in a cover (not shown) which encloses the spool 112 in a water environment. It can now readily be seen that the length of wire spinning in the water between the outboard flange M and the turn being no coiled on the spool varies from a minimum length at the turn adjacent the outboard flange M to a maximum length at the turn adjacent the inboard flange 116. The longer the length of this wire spinning in the water during the uncoiling operation the greater the tension will be on the wire as it is pulled from the opening 26. Accordingly, this payout tension on the wire cycles between maximums and minimums as the layers of wires are uncoiled from the spool. The present invention minimizes this variation in payout tension.

FIG. 3 is a graph of spool radius versus spool length illustrating constant tension contours T for wire payed out from a submerged flanged spool of the type: shown in FIG. I. The payout of the wire is from the outside of the coil over the outboard flange and then along the central axis of the spool. These constant tension contours which are concave, can be determined empirically or by calculations. It should be noted from the graph that for a spool of the type shown in FIG. I the tension on the wire being payed out will increase as the length increases from the outboard flange to the particular turn of wire being unwound. This is due to die increasing hydraulic drag on the increasing length of wire which is spinning in the water about the coil between the outboard flange and the turn of wire. For a spool of a specified length this tension becomes a maximum for any layer of wire at the turn of wire adjacent the inboard flange of the spool and a minimum at the turn adjacent the outboard flange thereof. It should also be noted from the graph that as the radius of the drum of the spool increases the payout tension on the wire decreases. Accordingly, the constant tension contours T are drawn along points which properly balance spool radius and spool length to achieve a constant payout tension of the wire as it is being withdrawn from the spool.

We have discovered that by configuring the spool drum and the coil of wire to correspond to a pair of constant tension contours T that the payout tension on the wire can be limited to values between these constant tension contours. As shown in FIGS. 2 and 4 we have provided a spool 23 with wire 24 wherein the spool includes a drum 26 which is located between outboard and inboard flanges 28 and 30. In the same manner as the prior art spool (FIG. l) the wire 24 is payed out over the outboard flange 28 and thence along a tube or open ing 34 of a cover (not shown) enclosing the spool 23'. In the spool 23 we have selected to configure the exterior surface of the spool drum 26 with constant tension a surface of revolution of the T =30 lbs. This establishes a desired maximum tension which will be subjected on the wire 24 during payout. Next, we have selected. the outside configuration of the wire 2d coiled on the drum 26 to be a surface of revolution of constant tension contour T =20 lbs. This establishes a desired minimum tension which will be exerted on the wire 24 during payout. With such configurations of the spool'drum and coil of wire the tension on the wire 24 will vary only between 20 and 30 pounds during payout thereof. It is to be understood that the constant tension contours T =20 lbs. and 30 lbs. is only exemplary and that any pair of constant tension contours established on the chart of FIG. 2 could be utilized depending upon the design parameters. As shown in FIG. 4 the outside configuration of the coil of wire 24 on the spool 26 may be achieved by increasing the number of wire layers toward the inboard flange Fill.

In a broad concept of this invention the variation in payout tension on the wire can be minimized to some extent by simply providing the spool drum with an outside diameter which is greater at its inboard end 3@ than at the outboard end 28 and a curved surface therebetween. If desired the contour curves can be approximated by circular arcs arrived at by graphical trial and error. However, as described for the preferred embodiment, greater improvement is achieved by progressively increasing these curves according to a desired maximum constant tension contour T of the graph in FIG. 3. Further, even with a prior art cylindrical drum, the variation in payout tension on the wire can be minimized to some extent by winding the wire 24 with additional layers toward the inboard end 30. However, as described for the preferred embodiment, optimum success is achieved by winding the wire 24 according to a constant tension contour T on the graph of FIG. 3 on a drum which is also configured according to a constant tension contour.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

I. In a nonrotating spool for wire wherein the spool has a drum portion between inboard and outboard flanges, the improvement comprising:

said drum portion having an exterior surface which is concave in longitudinal axial cross section according to a predetermined maximum constant tension contour, the largest outside diameter of said concave exterior surface being adjacent said inboard flange, whereby variation in tension on a wire on the spool can be minimized when the wire is pulled along the central spool axis over the outboard flange thereof. 2. In a nonrotating spool with wire as claimed in claim 1 the improvement comprising:

wire wound on the drum portion in layers; and the number of layers of wire increasing from the outboard flange toward the inboard flange of the drum portion. 3. In a nonrotating spool with wire as claimed in claim 2, the improvement comprising:

the wire being wound on the drum to form an exterior surface which is concave in longitudinal axial cross section according to a predetermined minimum constant tension contour. 

1. In a nonrotating spool for wire wherein the spool has a drum portion between inboard and outboard flanges, the improvement comprising: said drum portion having an exterior surface which is concave in longitudinal axial cross section according to a predetermined maximum constant tension contour, the largest outside diameter of said concave exterior surface being adjacent said inboard flange, whereby variation in tension on a wire on the spool can be minimized when the wire is pulled along the central spool axis over the outboard flange thereof.
 2. In a nonrotating spool with wire as claimed in claim 1 the improvement comprising: wire wound on the drum portion in layers; and the number of layers of wire increasing from the outboard flange toward the inboard flange of the drum portion.
 3. In a nonrotating spool with wire as claimed in claim 2, the improvement comprising: the wire being wound on the drum to form an exterior surface which is concave in longitudinal axial cross section according to a predetermined minimum constant tension contour. 